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8 votes
8 votes
Pre calc question...pls help

Pre calc question...pls help-example-1
User Rasoul Zabihi
by
3.0k points

1 Answer

23 votes
23 votes


{\Large \begin{array}{llll} y=ab^x \end{array}} \\\\[-0.35em] ~\dotfill\\\\ f(-4)=1\hspace{5em}1=ab^(-4)\implies 1=\cfrac{a}{b^4}\implies b^4=a \\\\[-0.35em] ~\dotfill\\\\ f(4)=69\hspace{5em}69=ab^4\implies \stackrel{\textit{substituting from the 1st equation}}{69=(b^4)b^4\implies 69=b^8} \\\\\\ \sqrt[8]{69}=b\implies (69)^{(1)/(8)}=b \\\\[-0.35em] ~\dotfill


y=√(69)\left( (69)^{(1)/(8)} \right)^x\implies \boxed{y=√(69)(69)^{(x)/(8)}} \\\\\\ \textit{when x=6.5, what is

User Victor Sorokin
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